1. Field of the Invention
This invention relates to a retainer, more particularly to a retainer for securing together upper and lower shipping containers.
2. Description of the Related Art
Referring to FIGS. 1 and 2, to prevent a stack of shipping containers 12 from shifting away from each other or slipping into the sea from a container ship 11, aside from using a binding device (not shown) to fix the shipping containers 12 to the container ship 11, a plurality of retainers 13 are further used to engage corner pieces 14 of each pair of superimposed shipping containers 12. Each of the retainers 3 has upper and lower retaining members 132, 133, and an intermediate member 131 between the upper and lower retaining members 132,133.
In use, the upper retaining members 132 of the retainers 13 are first inserted into the corner pieces 14 of one shipping container 12, after which a magnetic hanging system 15 is used to move the shipping container 12 to the container ship 11. The lower retaining members 133 of the retainers 13 are then inserted into the corner pieces 14 of another shipping container 12 that is disposed on the container ship 11, thereby securing together the two superimposed shipping containers 12.
Under normal circumstances, the shipping containers 12 maintain their orderly arrangement in a stack for the duration of the journey. However, when the container ship 11 encounters heavy wind and big waves, or bumps into something, the center of gravity of the shipping containers 12 usually follows the body of the container ship 11 and deviates. This results in some of the lower retaining members 133 of the retainers 13 being moved out of the respective corner pieces 14, so that some of the shipping containers 12 may shift away from the stack and may even fall off into the sea.